1. Field of the Invention
The present invention relates to building forms and, more particularly, to metallic forms for making concrete columns, walls, and similar structures.
2. Description of the Prior Art
Concrete columns, such as the type used as supports for buildings, bridges, and the like are made by pouring concrete into a form comprising a plurality of stacked, attached, hollow metallic form units. Each unit is made of half-sections which are attached to each other at their vertically aligned joints by a plurality of fasteners spaced about a foot apart. Since the form assemblies can vary from four to 20 or more feet in height, a considerable number of fasteners are required to be inserted each time an assembly is made. After the concrete has hardened, the fasteners are then removed one by one so that the section halves can be parted from the concrete and moved to a new location for reassembly to provide a form for the next column to be poured. The process of attaching and removing the individual fasteners is time-consuming, results in extensive labor costs, and the materials used in the fastening process, such as nuts and bolts, are easily lost.
While various "quick release" techniques employing elements such as pins, wedges, sliding fasteners, and the like have been used to secure section halves in place, they have had the disadvantage that they still have to be individually removed and replaced, thereby requiring extensive manual labor. In addition, some of the devices have had a problem in achieving a desired positive lock of the forms in place.